Applications of XPS, AES, and TOF-SIMS

Transcription

1 Applications of XPS, AES, and TOF-SIMS Scott R. Bryan Physical Electronics 1

2 Materials Characterization Techniques Microscopy Optical Microscope SEM TEM STM SPM AFM Spectroscopy Energy Dispersive X-ray Spectroscopy (EDX) X-ray Diffraction (XRD) Electron Energy Loss Spectroscopy (EELS) Auger Electron Sepctroscopy(AES) X-ray Photoelectron Spectroscopy (XPS) Secondary Ion Mass Spectrometry (SIMS) Fourier Transform Infrared Spectroscopy(FTIR) Raman Spectroscopy Photoluminescence (PL) Dynamic Light Scattering (DLS) 2

3 Materials Characterization Techniques Microscopy Optical Microscope SEM TEM STM SPM AFM Spectroscopy Energy Dispersive X-ray Spectroscopy (EDX) X-ray Diffraction (XRD) Electron Energy Loss Spectroscopy (EELS) Auger Electron Sepctroscopy(AES) X-ray Photoelectron Spectroscopy (XPS) Dynamic Secondary Ion Mass Spectrometry (D-SIMS) Time-of-Flight Secondary SIMS (TOF-SIMS) Fourier Transform Infrared Spectroscopy(FTIR) Raman Spectroscopy Photoluminescence (PL) Dynamic Light Scattering (DLS) Used for surface, thin film, and interface analysis 3

4 Surface Chemical Analysis Techniques Depth of Analysis Courtesy of EAG Laboratories 4

5 Auger Electron Spectroscopy (AES) 5

6 What Information Does Auger Provide? Surface composition at high spatial resolution Secondary Electron Imaging (3 nm) Elemental analysis (spectra) (8 nm) Elemental imaging (mapping) High energy resolution spectra, imaging and depth profiling Sputter depth profiling Reveals thin film and interfacial composition 6

7 Semiconductor Defect Identification with Auger S C N O F Al Particle Si Kinetic Energy (ev) Auger detects Al particle Si SE 5kV Petal Si C Si C O F O "Petal" Off "Petal" Si Kinetic Energy (ev) Auger detects C & F on thin petal Green=C Red=Al Blue=Si F 5kV Off Petal EDX does NOT detect C & F on Å thin petal 7

8 N(E) cps Auger Chemical State Analysis Al KLL Spectra of Native Oxide on Al Foil ev (Al oxide) 0.5% 0.1% ev (Al metal) Kinetic Energy (ev) Auger KLL spectrum of native oxide on Al foil measured on PHI CMA at 0.5% (blue) and 0.1% (red) energy resolution, after background subtraction. 8

9 Intensity Intensity Si Metal Auger Chemical State Analysis High Energy Resolution Imaging of Semiconductor Chemical States Composite Si KLL A Si KLL image with ROI areas B Si4 IC412_256.map: Pad Sep kv 10 na FRR 0.00 s Si4/-1 RSF PHI Silicide 0.1 % high energy resolution spectral windowed mapping Kinetic Energy (ev) C 20 µm 20 µm Si KLL Basis Spectra LLS fitting from the basis spectra extracted from regions of interest Si Oxynitride Silicide Elemental Si Kinetic Energy (ev) 9

10 Auger Chemical State Analysis High Energy and Spatial Resolution Imaging of Semiconductor Chemical States IC.401.sem: Pad Sep kv 10 na FRR SEM/-1 A SEI SEM IC412_256.map: PHI Pad 41 Si4/-1RSF 4094 B IC412_256.map: PHI Pad Sep kv 10 na FRR Sep s 2012 kv 10 na FRR 0.00 s Si KLL Peak Si4 Area Si4/-1RSF C Silicide Si4.ls1 RSF PHI Oxynitride (blue) 20 µm 20 µm 20 µm Elemental Si (green) IC412_256.map: 20 Pad µm 41 IC412_256.map: PHI Pad 41 IC412_256.map: PHI Pad 41 PHI 20 µm µm Sep kv 10 na FRR 2012 Sep s 10.0 kv 10 na FRR 2012 Sep s10.0 kv 10 na FRR 0.00 s Si4/-1 D Si4/-1 RSF Si4/-1RSF E Si Oxynitride F Si4.ls2 Si4.ls3 Si4.ls1+Si4.ls2+Si4.ls Si Chemical States Elemental Si RSF 47.0 Silicide (red) 20 µm 20 µm 20 µm 20 µm µm 200 µm FOV SEI of a semiconductor bond pad 0.1% energy resolution data µm 0.0 Auger Color Overlay 20kV 10nA 256x256 pixels Green: Elemental Si Blue: Si Oxynitride Red: Silicide 10

11 PHI 710: Nanoscale Depth Profiling Intensity SEI 60 nm Diameter Si Nanowire Surface Spectrum of Nanowire 1 P O F FOV: 2.0 µm 0.5 µm P from the growth gas is detected on the surface of a Si nanowire Si C Atom % Si 97.5 P Kinetic Energy (ev) 20 kv, 10 na, 12 nm Beam 11

12 PHI 710: Nanoscale Depth Profiling Phosphorous (atom %) 500 V Ar sputter depth profiling shows a nonhomogeneous radial P distribution The data suggests Vapor- Solid incorporation of P rather than Vapor-Liquid- Solid P incorporation Depth Profile of the Si Nanowire Sputter Depth (nm) 12

13 X-ray Photoelectron Spectroscopy (XPS) 13

14 What is XPS used for? Metal We have analyzed: Plastic Paint Glass Ceramic Fabric Semiconductors Biomaterials Composites Mirrors, lenses, windshields, integrated circuits, circuit boards, fruit flies, teeth, heart valves, pacemakers, stents, relay contacts, make-up, shampoo residue on hair, moon rocks, space shuttle tiles, mold, hip joints, dental floss, dirty socks, solid rocket fuel, gaskets, brake pads, lipstick, adhesive labels, paper, ink, Mr. Potato Head, etc. 14

15 XPS: Quantitative Elemental & Chemical Information c/s -O KLL -O1s -C1s -O2s c/s Atom % C 70.9 O 29.1 % of C 1s CH 62.7 C-O 20.2 O=C-O 17.1 O=C-O C-O C 1s CH Binding Energy (ev) XPS survey spectra provide quantitative elemental information Binding Energy (ev) High resolution XPS spectra provide quantitative chemical state information 15

16 Argon Gas Cluster Beam (GCIB) cleaning of Polyimide c/s c/s As received CH x contaminated After GCIB cleaning C-N C-O C-C (including contaminants) 45.0 (at.%) of C 1s C-N C-O C-C 37.9 (at.%) of C 1s N-C=O pp* N-C=O pp* Binding Energy (ev) Binding Energy (ev)

17 c/s c/s c/s Argon Gas Cluster Ion Beam (GCIB) cleaning of TiO x After cleaning Ti 2p O 1s C 1s 4.5 x After cleaning As received As received As received Binding Energy (ev) Binding Energy (ev) After cleaning Binding Energy (ev)

18 Atomic Concentration (%) XPS Depth Profile of Thin Films Sputter Depth Profile Oxygen Oxygen Titanium Nitrogen Niobium Sputter depth profile of an architectural glass coating 40 Titanium 30 Silicon Silicon 20 Nitrogen 10 Aluminum Sputter Depth (nm)

19 Atomic Concentration (%) GCIB Depth Profile of Organic LED Layers 100% Sputter Depth Profile of a Graded OLED Test Structure 0% 100 nm Si Native Oxide N 1s (BPhen) 10X 10 kv Ar Sputtering C 1s N 1s (TCTA) 10X N1s (TCTA) N1s (BPhen) 60 O 1s Si 2p TCTA Binding Energy (ev) BPhen Sample courtesy of Prof. Russell Holmes, U of MN Sputter Depth (nm) 19

20 Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS) 20

21 Surface Chemical Analysis Techniques Courtesy of EAG Laboratories 21

22 What is TOF-SIMS used for? Surface Mass Spectra with MS/MS: Identification of all atomic and molecular species on surface High sensitivity and molecular specificity Imaging 2D elemental and molecular distributions Depth Profiling Elemental and molecular depth distributions FIB-TOF Accurate 3D distributions of heterogeneous materials

23 Schematic of the PHI nanotof II

24 PHI nanotof II with MS/MS

25 Counts TOF-SIMS of a Commercial Polypropylene MS 1 Spectrum of Polypropylene surface 1.2E E+6 C 3 H 8 N Na K E+5 C 7 H E E+5 29 C 9 H 12 N E

26 Unambiguous Identification of m/z 304 polymer additive Benzalkonium, m/z TOF-SIMS MS/MS Spectrum of Unknown MS2 Pos NIST Library MS/MS Spectrum ESI with QQQ Head to Tail MF=692 RMF= Benzyldodecyldimethylammonium

27 TOF-SIMS Imaging Region 1 Spectrum Primary Ion Beam Chemical Map 1 Total Ion Image Total Area Spectrum m/z Region 2 Spectrum m/z Chemical Map 2 m/z Sample Spectra from selected areas of the total ion image or images from selected peaks of the total area spectrum can also be obtained for complete analysis after data acquisition. 27

28 O 2 + Ion Gun Sputter Depth Profiling Excellent Comparison between TOF-SIMS vs D-SIMS Layer (Depth Resolution) D-SIMS TOF-SIMS 28

29 Conclusions Auger Electron Spectroscopy (AES)» Use for highest spatial resolution surface analysis X-ray Photoelectron Sepctroscopy (XPS)» Use for quantification of elements and oxidation states Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS)» Use for identification of organic compounds» Use for trace level surface analysis 29